1. Field of the Invention
The present invention relates to the field of display technology, and in particular to an organic light emitting diode (OLED) packaging method and an OLED packaging structure.
2. The Related Arts
In the field of display technology, the flat panel display technology, including liquid crystal display (LCD) and organic light emitting diode (OLED), have gradually taken the place of cathode ray tube (CRT) displays. Among them, OLED has various advantages, including natural light, low drive voltage, high emission efficiency, short response time, high sharpness and contrast, approximately 180 degree view angle, wide range of operation temperature, and being capable of achieving flexible displaying and large-area full-color displaying, and is widely used in for example mobile phone screens, computer displays, and full-color televisions and are considered the display device having the most prosperous development.
An OLED comprises, in sequence, an anode formed on a substrate, an organic emissive layer, and a cathode. The primary issue, and also the greatest problem of an OLED, that constrains the progress of the OLED industry is the relatively short lifespan of the OLED. The cause that leads to the relatively short lifespan of the OLED is that electrodes of an OLED device and an organic substance making the light emissive layer are extremely sensitive to moisture and oxygen contained in the atmosphere and electrochemical corrosion may easily caused in an environment containing moisture and oxygen to damage the OLED device. As a consequence, an OLED must be properly packaged to prevent invasion of moisture and oxygen into the interior of the OLED.
Packaging is a link of vital importance in a manufacturing process of an OLED display. The quality of the packaging directly affects the sealing performance of the OLED display, which in turn affects the lifespan and quality of the OLED. Conventionally, the primary solution taken for an OLED display is the so called “dam and desiccant” process. As shown in FIG. 1, an OLED packaging structure, which adopts the “dam and desiccant” solution, generally comprises a thin-film transistor (TFT) substrate 100, a package lid 200 opposite to the TFT substrate 100, an OLED device 110 that is located between the TFT substrate 100 and the package lid 200 and mounted to the TFT substrate 100, a loop of desiccant 120 arranged outside and around the OLED device 110, and a loop of a dam 130 arranged outboard the desiccant 120 and bonded to both the TFT substrate 100 and the package lid 200. A process of manufacturing the above packaging structure is to coat the loop of desiccant 120 on the package lid 200 at a location corresponding to an outer circumference of the OLED device 110 and the a sealing dam 130 made of for example epoxy resin is applied to bond the TFT substrate 100 and the package lid 200 to each other. Due to a difference of air pressure between the inside and outside of the packaging structure, such a packaging process often cause a drawback of resin being flushed away in bonding the TFT substrate 100 and the package lid 200.
Thus, it is desired to provide an OLED packaging method and an OLED packaging structure that are novel in order to address the above problems.